Apparatus for applying tipping to propeller blades



Aug. 2, 1949.

Filed Dec. 11, 1946 A. H. LAMBERT ET AL APPARATUS FOR APPLYING TIPPINGTO PROPELLER BLADES 3 Sheets-Sheet 1 IN EN 0R5 V T 412527 64 z/waier1949. A. H. LAMBERT ET AL 2,477,626

APPARATUS FOR APPLYING TIPPING TO PROPELLER BLADES 3 Sheets-Sheet 2arr/away:-

1949. LAMBERT AL 2,477,626

IPPING APPAR US F APPLYIN TO FR LLER BLADES Filed Dec. 11, 1946 5Sheets-Sheet 3 I N V EN TORS' 41 51557 H [WA/i587 m g M new 55%? I x 1BY WM @2 Patented Aug. 2, 1949' UNITED STATES PATENT OFFICE APPARATUSFOR APPLYING IIPPING TO PR'OPELLER BLADES Albert H. Lambert, Dayton, andIra. R. Barr, Yellow Springs, Ohio ("Granted under the act of March 3,1883, as

amended April 30, 1928; 370 '0. G. "757") The invention described hereinmay be manu- Iactured and used by or for the Government for governmentalpurposes without payment to us of any royalty thereon.

This invention relates to an apparatus and a method for applying tippingto the leading edge of a propeller blade.

One of the essential objects of this invention is to provide a novelapparatus whereby the metal tipping, which is usually a sheet ofstainless :steel, can be quickly and securely applied onto the leadingedge of a propeller blade of wood, metal, plastic or the like, andwithout employing any rivet holes or .rivets or screws.

.A more particular object of this invention is to provide a novelapparatus or tipping jig whereby the tipping canbe readily applied tothe propeller blade by employing .a suitable adhesive and pressure,thereby actually strengthening the blade, and thus obviating thecustomary practice :of drilling holes in the blade and the tipping andinserting rivets or screws therein which former practice weakened theblade and the tipping and also required much additional time and labor.

Another object of this invention is to provide such an apparatus for.securing tipping onto the edge of a propeller blade by means ofadhesive and pressure wherein pliable tubular means is utilized to bearupon the outer surface of the tipping and is operable by pneumaticpressure, .so as to apply the pressure uniformly over the en- 'tiretipping surface and secure the tipping throughout its entire area withuniform firmness onto the edge of the blade.

Another object of this invention is to provide a novel method ofapplying tipping on the edge of a propellerblade by the use of adhesiveapplied with pressure, or with heat and pressure, so to make suchapplication considerably easier and speedier and thus less expensive,.and also render ing a sturdier construction, than was accmp'lished bythe former procedure of drilling holes in the blade and in the tippingand then insertiing rivets or screws therein.

A further object of this invention .is to provide a novel method .ofsecuring tipping onto a propeller blade whereby regulated heates well asconstant high pressure is applied in the process for a certain length oftime, so that a hot-setting adhesive as well as 'a cold-setting adhesivemay be used in binding the tipping onto the edge of the blade.

These and various other objects and advantages are attained with thisinvention, as will be. come apparent from the following description.taken in connection with the accompanying drawing wherein the inventionis shown its preferred form, it being evident that other arrangementsand forms of construction may be resorted to in carrying out the objectsand purposes of this invention.

In the drawings:

Fig. l is a side elevational view of the apparatus, parts being brokenaway.

Fig. .2 is an end elevational view thereof, with the hub support shown:in section.

Fig. 3 is a vertical sectional view. taken 'on line 3--3 of Fig. 1. I

Fig. i is a plan view, with parts broken away.

Fig. 51s an enlarged fragmentary section, taken across the pressure hosetogether with the insulating layer and glass fiber layer thereon,pressing the tipping with the adhesive onto the ,propeller blade.

This apparatus briefly comprises a supporting frame H which in thisdisclosed form of construction includes a base 12 carrying thereon means1.3 for supporting one edge part of the propeller blade 14, and means 15for supporting the hub part 15 of the blade; and also includes holdingmeans 11 for holding the tipping 1'8 in place upon the opposite edgepart of the blade and which preferably includes means T9 for applyingpressure or heat and pressure for a certain length of time to thetipping, so as to secure it evenly and firmly by the interposed adhesive means onto the blade edge.

The base 12 of the frame 11 includes two supporting beams 21 extendinglongitudinally of the frame I l, and held together by several baseplanks 22 secured thereunder.

The blade supporting means 18 includes a set of supporting beams .23secured upon said beam 21, crosswise of the frame; and blade supportingmembers 2-! mounted adjustably upon said beams 23, as by companiongroove and tongue means 23' and 24 provided on said beams 23 and on saidmembers 124. and by use of clamping elements 225 in the form of loopedrods, each having its upper curved part engaging in a notch 233 providedon the top shoulder of a member 24,, and the lower eurved partsurrounding a beam 23. A wedge '21 is driven between the bottom of abeam 23 and of a rod 25,.to force and retain the member 2 tightly ontothe beam 23. These beams 23 are arranged in pairs and each pair of beamshas the adjoining faces 28 slanting to provide a trough therebe'tween,.so as to fit the contour of the propeller blade ll, while a layer orlining 29 of pliable material, for instance felt or wool, is secured oneach face 28 and has sufficien-t creep to adjust itself snugly to thecontour of the blade. Said members 24 are thus adjustable along saidtongue and groove means on beams .23, to accommodate propeller "b1adesof different sizes.

Iihe means l5 for supporting the hub part 16 of the blade comprises afooting bar 34' secured upon the beams 2| at one end of the frame andcarry- 3 ing a lower hub supporting bracket 32 thereon, which ispreferably made of metal in the form of a disc fixed on bar 3| andhaving an arm 33 arising therefrom. Said means also comprises hubclamping means which is mounted on arm 33, and this means includes alower hub plate 34, preferably a metal disc, having a pair of arms 35integral thereon and depending'therefrom and provided with a slot 36 forreceiving a bolt 31 which extends through arm 33, to, allow foradjustrnent of the arm 35 with disc 34 on the fixed bracket 32. An upperhub disc 4| of metal has a neck 42 thereon, and a bolt 43 extendsthrough said neck and through a central aperture in disc 34- and througha bushing 44 positioned between said discs,.while a pair of circularwood plates 45 are placed between the ends of said bushing 44 and ofsaid discs 34 and 4| to engage and clamp the twoside faces of the hubportion lit, by the tightening of either the upper or the lower nut 45or 4'! on said bolt 43. A slot 48 in the two arms 35 receive and holdthe lower nut 4! from turning whileupper nut 46 is being applied on thebolt. This bolt has excess length to accommodate blade hubs of differentsizes.

The means |5 herein supports the hub portion l6 of the propeller, whilethe trailing edge part of the blade 14' is supported in the set oftroughs formed between the several pairs of pliable layers 29 on thepairs of slanting faces 28 of members 24.

This supporting means l5 as disclosed is adapted best for supporting afixed pitch propeller, but it is apparent that a detachable propellerblade may be similarl supported hereby.

In this form of apparatus disclosed herein the upper holding means I1 isshown mounted over the leading edge of the propeller blade, whereon thetipping I8 is being applied, and is provided with special pressureapplying means l9 to bear upon the outer side of said tipping and forceit onto the blade edge. Herein the means II includes a holding memberwhich is in the shape of a beam 5| extending over the edge of the bladeand over the tipping thereon, longitudinally of the frame H, and has themeans |9 interposed between it and the tipping |B. The beam 5| ishingedl mounted on the frame and is movable upwardly from the supportingmeans Hi, to facilitate mounting the propeller blade and the tippingthereon. Said holding beam 5| hinge bars 52 extending crosswise thereofand secured thereon by bolts 53. Hinge elements 54 are provided, eachpreferably consisting of a looped rod having its upper part resting in anotch 55 provided on the top of one of the bars .52 with a cover plate56 secured thereover; while the lower curved part of each looped rod 54is separated and the two ends 54' are engaged in apertures at oppositesides of one of the beams has a set of 23, thus affording a swingingmovement or hing of each hinge element 57 is mounted oiT center in aneccentric 58 which is seated on the end part of a cross-bar 52, oppositeplate 56; and a handle 59 on said eccentric facilitates swinging it intoclamping position, as shown in full lines in Fig. 3, or into releaseposition, as shown in dotted lines therein. Two washers 60 are posi- 4tioned at the opposite sides of'each eccentric 58 and welded to thehinge rod 51, to retain the eccentric against sidewise movement.

The pressure applying means I9 is associated with the holding beam l1,and preferably consists of a pliable tubular member 6| expansible bypneumatic pressure, and in this form of construction as disclosed hereina fire hose is conveniently and economically utilized which is mountedin an arched groove 62 provided in the nether face of beam 5|. Said hoseis of a size to extend over the full length of the blade I4 and of thetipping I8 and so as to cover substantially the entire outer surface ofthe tipping, about as indicated in Fig. 3, wherein the hose is showndeflated. Suitable pressure inlet means 63 on the hose 5| admits apressure medium into the hose, such as compressed air, stream, or otherexpansible fluid that may be placed under heavy pressure. 7

In cases where it is desired to apply heat along with the pressure, tosecure the tipping on the blade, as by the use of hot-setting adhesive,hot steam can be used instead of cold air as the pressure medium intubular member 6|. However, said pressure applying means i9 is hereinshown as furthermore provided with a special heating means 55 adapted tobe used for heating the tipping and the adhesive material whenever thatis desirable. This means 65 is shown herein as comprising an electricheating coil 65, an Omaloy resistance heater being suitable with currentsupplied through an electric conductor 51, and having an insulatinglayer 68 of asbestos placed between the heater and the hose, and a layer59 of fiber glass cloth placed inward of the heating coil and adjoiningthe tipping l8, soas to heat said tipping and the adhesive ll) that wasapplied as coatings or linings on the two joinable parts of the blade l4and the tipping l8, as best shown in Fig. 5.

In the procedure of tipping a propeller blade by the use of thisapparatus, the edge part of the blade l4, whether of metal or wood orother material, is sanded on the surface to be covered by the tipping,parallel to the line of gyration, to roughen the same for providing astronger bond.

The tipping is preformed in harmony with the surface of the blade edge,and its inside surface is preferably roughened, care being taken thatrust or oxide or scales are removed therefrom as well as any grease ordust.

The propeller is then placed on the support and has its hub portion [6secured in the hub clamping means I5, and is brought into position sothat the blade |4 rests within the set of troughs provided by the pairsof slanting face portions 28 with linings 29 on thev supportin members24, as best seen in Fig. 3.

The adhesive material 70 used may be either cold-setting adhesive orhot-setting adhesive. By the use of the cold-setting adhesive a film ofthe cement is provided between the tipping and the blade edge, beingpreferably applied in the form of a thin film to the joinable surfacesof both the tipping and the blade edge, and allowed to dry for about 15minutes or until the film thereof becomes tacky. Said cement may beCasco Flexible cement, a dilutable water-dispersion of casein andsynthetic rubber latex in liquid form. The tipping is then applied inits proper position on the blade edge, and the pressure applying meansl9 as well as the holding means I! are then brought into holdingposition upon the entire outer surface of the tipping, and

the eccentric 53 is locked in position. The pres sure medium is thenapplied to the hose to in flate it to substantially a pressure ofapproximately 100 p. s. i., thereby pressing the entire tipping with theadhesive thereon firmly and uni formly onto the edge of the blade. Theapparatus and the tipping is thus left under the pres sure forapproximately 48 hours. No heating means is required with thiscold-setting procedure.

With the use of hot-setting adhesive, a thermosetting synthetic resin ispreferably used, for which the substance known as "Redux is suitable.The adhesive is provided between the tipping and the blade edge, and athin film of the adhesive is preferably applied to both of the joinableportions of the tipping and of the blade; while a resistance heater withits electric connections, being provided with the layer of glass clothinsulation thereunder and with the layer of asbestos insulationthereover, is placed on the tipping for the entire length thereof, andthe hose 6: is applied thereover, whereupon the holding means is securedin position. The heater may also be connected to the hose and appliedtogether therewith. The pneumatic pressure is applied to the hose,approximately 100 p. s. i., and the electric current is applied to theheater to raise the temperature at the line of the adhesive toapproximately 300 F., measured with a thermooouple. This temperature isdeveloped in about 3 minutes, and said temperature is then maintainedfor about 10 minutes when the current is cut off. About 13 minuteselapses for said temperature to drop to a normal degree, and the bladetogether with the tipping which is very firmly and evenly securedthereon may then be removed from apparatus.

This apparatus and these methods of applying the metal tipping to eithera wood or a metal propeller blade, by the use of adhesive and pressure,have provided excellent results as proven by various whirl tests andengine tests conducted therewith. These tests have disclosed theproduction of a more even and secure bond between the tipping and theblade edge, by the use of this method and apparatus, than had beenaccomplished heretofore with the customary procedure of providing rivetholes in both the tipping and the blade and then securing rivets orscrews therein, and a stronger blade and tipping are hereby produced,due to the absence of rivet holes in the tipping and in the blade.

By the use of this apparatus and method, stainless steel tipping can nowbe applied efficiently and securely to aluminum alloy propellers, aswell as to other metal, wood or plastic propellers.

Our tipping jig is adapted for use with either fixed pitch or detachableblade propellers, and for different models.

The pivot action of the hub supporting means will enable properpositioning of any type blade of a fixed pitch propeller.

This apparatus can be quickly set up and speedily used in tipping ablade, thus saving time and laborand effecting economy, and it is alsoportable to facilitate its use.

We claim:

1. An apparatus for applying tipping to a propeller blade with adhesivebetween their adjoining parts, said apparatus comprising a supportingframe, means on the frame for embracing and supporting the hub part ofthe propeller and being adjustable angularly about the blade axis tosuit different forms of propellers and different degrees of blade twist,means longitudinally spaced on the frame for embracing the trailing edgepart of the blade and being adjustable transversely on the frame toaccommodate blades of different sizes and shapes, and means in the formof an inverted trough positioned over the leading edge of the blade andincluding expansible means for engaging the tipping to press it with theadhesive firmly and evenly onto the edge of the blade.

2. An apparatus for applying tipping to a propeller blade while both thetipping and the blade edge have adhesive provided on their adjoiningparts, said apparatus comprising a supporting frame, means thereon forsupporting and securing the hub part of the propeller and beingadjustable' angularly about the blade axis for accommodatin propellersof different types and different degrees of blade twist, meanslongitudinally spaced on the frame for supporting the trailing part ofthe blade and being adjustable transversely of the frame to accommodateblades of difierent sizes and shape, holding means hingedly mountedabove the blade supporting means and including means for securing theholding means in position over the blade, and tubular means retained inposition by said holding means to extend over the entire outer surfaceof the tipping and being expansible by pneumatic pressure for forcingthe tipping with its adhesive firmly and evenly onto said leading edgeof the blade.

3. The subject matter set forth in claim 2, and wherein heating means isprovided to overlie the tipping for heating it and said adhesive.

4. An apparatus for applying tipping to a propeller blade, where alining of adhesive is provided between the adjoining parts of thetipping and the blade, said apparatus comprising a supporting frame,means thereon embracing the hub part of the propeller and beingangularly adjustable about the blade axis for accommodating blades ofdifferent sizes and twist, means longitudinally spaced apart on theframe including cushioned trough-shaped means for supporting thetrailing part of the blade and being transversely adjustable toaccommodate blades of different sizes and shapes, holding means hingedlymounted on the blade supporting means above said blade supporting meansand including a beam and means for securing it in position over theblade, and a pliable tube retained in position by a groove in theunderside of said beam for engaging the entire outer surface of thetipping and being expansible by pneumatic pressure for forcing thetipping with its adhesive firmly and evenly onto said leading edge ofthe blade.

ALBERT H. LAMBERT. IRA R. BARR.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,618,536 Junkers Feb. 22, I9272,391,426 Kramer et al. Dec. 25, 1945 2,407,528 Antonson Sept. 10, 19462,417,226 Weyant Mar. 11, 1947

